Core-Shell Structured Polystyrene Coated Carbonyl Iron Microspheres and their Magnetorheology

Quan, Xuemei; Chuah, Weihuan; Seo, Yongsok; Choi, Hyoung Jin

doi:10.1109/tmag.2013.2278291

Cited by 22 publications

(17 citation statements)

References 29 publications

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“…19 Several methods can enhance sedimentation stability, including the addition of surfactant systems 20 or nano-sized particles such as fumed silica, 21 organic clays, 22 carbon nanotubes 23 or graphite micro-particles. Also many polymers have been used as shell materials, e.g., poly(methyl methacrylate) 26 or polystyrene, 27 which were synthesized via both dispersion and suspension polymerizations. Therefore, the application of a polymer coating on the surface of the particles seems to be a wise strategy to counter this drawback.…”

Section: Introductionmentioning

confidence: 99%

A facile controllable coating of carbonyl iron particles with poly(glycidyl methacrylate): a tool for adjusting MR response and stability properties

et al. 2015

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This study is focused on the controllable coating of the carbonyl iron (CI) particles widely applied in magnetorheology. These particles were grafted with poly(glycidyl methacrylate) (PGMA) with narrow polydispersity via surface-initiated atom transfer radical polymerization. Two types of core-shell particles differing in molecular weights of grafted polymer chains were synthesized. The effect of shell thickness on the thermo-oxidation stability of particles as well as the sedimentation stability of their silicone oil suspensions was evaluated. The successful coating process was confirmed by Fourier transform infrared spectroscopy and energy-dispersive spectrometry. The differences in the magnetic properties of bare and coated CI particles were clarified through vibrating sample magnetometry. Due to the controllable length of the PGMA grafts, the magnetic properties remain almost the same as those for bare CI. The magnetorheological (MR) behavior of silicone oil suspensions containing 60 wt% of bare CI particles as well as PGMA-coated analogues was investigated in the absence and in the presence of various magnetic field strengths, demonstrating the negligible impact of surface modification on final MR performance. Thus, the grafting of the particles with PGMA negligibly affected magnetic properties but considerably enhanced thermo-oxidation and sedimentation stabilities. Finally, a novel tensiometric method for sedimentation stability measurements of MR suspensions was successfully implemented.

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Section: Introductionmentioning

confidence: 99%

A facile controllable coating of carbonyl iron particles with poly(glycidyl methacrylate): a tool for adjusting MR response and stability properties

et al. 2015

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“…The grafted polystyrene coating on the CIP surface shows a better distribution than previous CIP/polystyrene studies. 30,31,38,41 It was also observed that the particles' diameter has slightly increased by 0.2 μm due to the coating of polystyrene. Due to the minuscule difference in the diameter, there was no significant influence of the coated CIP on the MRE sample preparation.…”

Section: Morphology Of Coated Cipmentioning

confidence: 94%

“…Therefore, it is crucial to determine the required parameters in this polymerization. Thus, in this polymerization procedure, all parameters have been optimized by referring to other studies 31,[38][39][40] as well as after a few attempts of polymerization steps.…”

Section: Grafting Of Polystyrene On the Cipmentioning

confidence: 99%

Enhancement of the rheological properties of magnetorheological elastomer via polystyrene‐grafted carbonyl iron particles

Jamari

Nordin

Ubaidillah

et al. 2021

J of Applied Polymer Sci

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In this work, carbonyl iron particles (CIP) was grafted with polystyrene coating on its surface via polymerization method, and the coated-CIPs were then embedded into a silicone rubber with the ratio of 70:30 of CIP to silicone rubber in order to enhance the rheological properties of magnetorheological elastomer (MRE) in terms of lower initial storage modulus and higher MR effect. By using field emission scanning electron microscopy (FESEM) that is equipped with the energy dispersive X-ray spectroscopy for elemental analysis, it was observed that elements of C, N, O, Si, Fe, Br, Cu, and Sn were detected, confirming that the coating layer has been successfully developed on the CIP.Additionally, the investigation of the rheological characteristics was conducted at 25 C with three different sweep conditions using rheometer MCR 302.Firstly the strain amplitude was swept from 0.001% to 10% strain with 1 Hz frequency. Then, the frequency was varied from 1 Hz to 100 Hz under 0.01% strain at an applied current of 0-5 A. Lastly, the current was swept from 0 to 5 A under 0.01% strain amplitude and 1 Hz excitation frequency. It was discovered that the storage modulus of the polystyrene-coated CIP MRE is lower than that of uncoated-CIP MRE in all three sweep profiles. Advantageously, the magnetorheological (MR) effect of the coated-CIP MRE sample is higher than that of the uncoated-CIP MRE by 28.04%. Moreover, it was found that the coated-CIP MRE exhibited higher damping behavior with more than 0.14 loss factor than 0.12 loss factor of the uncoated sample. The dimensional stability of polystyrene coating on the CIP was an attributing factor to this enhanced damping behavior of the coated-CIP MRE. Thus, it became clear that the polystyrene-coated CIP embedment in MRE is more desirable than that of MRE with uncoated CIP.

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“…A core-shell structured polystyrene coated on CIP has been demonstrated by Quan et al (2014) [ 49 ] using dispersion polymerization too. In this work, the researchers also used MAA, PVP and AIBN as the surface pre-treatment agent, stabilizer and initiator, respectively.…”

Section: Coating Methodsmentioning

confidence: 99%

“…The re-dispersion of the particles after they were subjected to an external magnetic field was also improved, due to enhanced surface properties such as steric repulsion and electrostatic repulsion of the PMMA coating. A further investigation on the sedimentation stability property of coated magnetic particles in MRF has been conducted by Quan et al (2014) [ 49 ], where a Turbiscan instrument was used to compare the transmission percentage of polystyrene-coated CIP MRF and common silicone oil MRF. At the beginning of the experiment, both MRFs showed zero transmission which represented multiple incident lights scattered through the suspension which could not be transmitted due to many particles that were suspended in both MRFs.…”

Section: Particle Coating In Mr Materialsmentioning

confidence: 99%

Systematic Review on the Effects, Roles and Methods of Magnetic Particle Coatings in Magnetorheological Materials

et al. 2020

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Magnetorheological (MR) material is a type of magneto-sensitive smart materials which consists of magnetizable particles dispersed in a carrier medium. Throughout the years, coating on the surface of the magnetic particles has been developed by researchers to enhance the performance of MR materials, which include the improvement of sedimentation stability, enhancement of the interaction between the particles and matrix mediums, and improving rheological properties as well as providing extra protection against oxidative environments. There are a few coating methods that have been employed to graft the coating layer on the surface of the magnetic particles, such as atomic transfer radical polymerization (ATRP), chemical oxidative polymerization, and dispersion polymerization. This paper investigates the role of particle coating in MR materials with the effects gained from grafting the magnetic particles. This paper also discusses the coating methods employed in some of the works that have been established by researchers in the particle coating of MR materials.

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Core-Shell Structured Polystyrene Coated Carbonyl Iron Microspheres and their Magnetorheology

Cited by 22 publications

References 29 publications

A facile controllable coating of carbonyl iron particles with poly(glycidyl methacrylate): a tool for adjusting MR response and stability properties

A facile controllable coating of carbonyl iron particles with poly(glycidyl methacrylate): a tool for adjusting MR response and stability properties

Enhancement of the rheological properties of magnetorheological elastomer via polystyrene‐grafted carbonyl iron particles

Systematic Review on the Effects, Roles and Methods of Magnetic Particle Coatings in Magnetorheological Materials

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